OpenVPN and IKEv2 VPN
IKEv2 support has been added. OpenVPN is currently not supported by Apple’s MDM protocol, nor by Apple’s built-in VPN client.
Other MDM support OpenVPN and it's possible to do it thorugh a custom profile why is it not possible to do it wit simple mdm? see: https://openvpn.net/vpn-server-resources/provisioning-profile-example-1/